Estimated PV Generation PGE

[Redhill_qik]

I never filled anything out. Never saw anything from the installer. This is why I would like to know what PGE has for my account but ...

Ask PG&E and your installer for a copy of your full interconnect agreement? I saved a copy of the interconnect agreement that I signed with Tesla/PG&E, but I don't see the equipment details or orientation, so I think that must just be between the installer and PG&E.

Edit; seems like there are different interconnect forms 79-1151B-02 does include TIlt an Azimuth, but only one entry, probably more through the portal.

 

[swedge]

they will credit you based on the approved PTO panel count

Got it. If I understand it, the limit is applied month by month, is an estimate of the maximum amount your solar could produce, and the result is shown on the black&white bill pages. So if they have the right total size of your solar, you should be OK. I don't think they take actual weather or shading into account, just the season adjusted sun, panel specs, orientation and tilt, and inverter efficiency, if memory serves. Any self consumption, shade, clouds and such will reduce your production, but not PG&E's monthly estimate and limit, if I understand it correctly. So these give you some margin. As long as your export for the month is less than their estimate, the limit is moot.

Where one might get a reduced credit would be if more solar was added but PG&E not informed. Still self consumption would give breathing room.

PG&E will send you a copy of anything your installer gave them, and some of it may be accessible to you online. Installers fill out the paperwork and submit it on your behalf, so you may not have ever seen the actual documents which give the panel model numbers and orientations. There is a database of all the panel and inverter models which gives the specs. So unless your installer fudged on the forms, PG&E should have a pretty good basis for their estimations.

In my case, I have plenty of self generation, so I've never exported near the limit. Your system being much larger might get closer, but still if they've got good data, you should be fine.

As I understand it, the only point of the limit is to ensure that you are not grid charging off peak, and discharging to the grid at peak. This whole limitation thing is because you have storage and could, conceivably, cheat. Remember that PG&E gets a regulated profit based on their expenses, so being paranoid and doing all that extra paperwork to be sure you don't cheat simply makes them money.

SW

 

[h2ofun]

Got it. If I understand it, the limit is applied month by month, is an estimate of the maximum amount your solar could produce, and the result is shown on the black&white bill pages. So if they have the right total size of your solar, you should be OK. I don't think they take actual weather or shading into account, just the season adjusted sun, panel specs, orientation and tilt, and inverter efficiency, if memory serves. Any self consumption, shade, clouds and such will reduce your production, but not PG&E's monthly estimate and limit, if I understand it correctly. So these give you some margin. As long as your export for the month is less than their estimate, the limit is moot.

Where one might get a reduced credit would be if more solar was added but PG&E not informed. Still self consumption would give breathing room.

PG&E will send you a copy of anything your installer gave them, and some of it may be accessible to you online. Installers fill out the paperwork and submit it on your behalf, so you may not have ever seen the actual documents which give the panel model numbers and orientations. There is a database of all the panel and inverter models which gives the specs. So unless your installer fudged on the forms, PG&E should have a pretty good basis for their estimations.

In my case, I have plenty of self generation, so I've never exported near the limit. Your system being much larger might get closer, but still if they've got good data, you should be fine.

As I understand it, the only point of the limit is to ensure that you are not grid charging off peak, and discharging to the grid at peak. This whole limitation thing is because you have storage and could, conceivably, cheat. Remember that PG&E gets a regulated profit based on their expenses, so being paranoid and doing all that extra paperwork to be sure you don't cheat simply makes them money.

SW

I believe the limit is so you do not send back more than you were approved to do, which could impact things like safety with transformer size.

 

[Redhill_qik]

I believe the limit is so you do not send back more than you were approved to do, which could impact things like safety with transformer size.

Since it is a monthly aggregate export that would not work. This only applies to systems with battery storage, so my understanding is that prevents cost shifting by recharging at lower Off-Peak and then discharging at Peak.

 

[h2ofun]

Since it is a monthly aggregate export that would not work. This only applies to systems with battery storage, so my understanding is that prevents cost shifting by recharging at lower Off-Peak and then discharging at Peak.

Since batteries cannot discharge to the grid.

Bottom line is PGE will only give you up to the max calculation based on the number and size of panels they have approved. Not clear my installer provided anything more than this to PGE. Since is why I would love to have from PGE the exact info they have, and formula, that shows how they come up with the monthly max export info. With using in the home, I hope to no longer never exceed. I had when they had not updated the number of panels they approved last year. Will see what happens during the next few max output months.

 

[Redhill_qik]

Since batteries cannot discharge to the grid.

Bottom line is PGE will only give you up to the max calculation based on the number and size of panels they have approved. Not clear my installer provided anything more than this to PGE. Since is why I would love to have from PGE the exact info they have, and formula, that shows how they come up with the monthly max export info. With using in the home, I hope to no longer never exceed. I had when they had not updated the number of panels they approved last year. Will see what happens during the next few max output months.

Batteries can and do discharge to the grid and that is why this calculation is there for battery accounts. The recent virtual battery pack is one example, misconfigured CTs is another (my system will discharge 50-80W at times) and then there is the installer options

 

[MJ_CA_2019]

Since batteries cannot discharge to the grid.

Bottom line is PGE will only give you up to the max calculation based on the number and size of panels they have approved. Not clear my installer provided anything more than this to PGE. Since is why I would love to have from PGE the exact info they have, and formula, that shows how they come up with the monthly max export info. With using in the home, I hope to no longer never exceed. I had when they had not updated the number of panels they approved last year. Will see what happens during the next few max output months.

If the information provided to PG&E is correct, it seems impossible to ever exceed their estimated generation.
Your home loads are behind the meter, so unless you are adding some kind of rogue generation, or have literally all home loads turned off how could you even approach the generation estimate?

 

[miimura]

If the information provided to PG&E is correct, it seems impossible to ever exceed their estimated generation.
Your home loads are behind the meter, so unless you are adding some kind of rogue generation, or have literally all home loads turned off how could you even approach the generation estimate?

The NEM-PS billing system is set up to disallow export credit in excess of your estimated generation. If you installed more solar than PTO docs, you could easily do it. A rogue battery system that could charge off-peak and discharge during Peak could also create excess export credits. The Tariffs clearly specify how they will penalize you by deducting from Peak first, Part-Peak second, then Off-Peak if you have excess exports.

A fully permitted and PTO'd Tesla system will never run into these limits.

 

[BGbreeder]

I believe the limit is so you do not send back more than you were approved to do, which could impact things like safety with transformer size.

Given that PG&E asks for azimuth, I suspect that they are going one step beyond max solar/battery and trying to forecast/guesstimate future production by hour/day, etc. If it were just max current, PG&E wouldn't need azimuth.

Just my $0.02...

BG

 

[h2ofun]

If the information provided to PG&E is correct, it seems impossible to ever exceed their estimated generation.
Your home loads are behind the meter, so unless you are adding some kind of rogue generation, or have literally all home loads turned off how could you even approach the generation estimate?

If I sent 100% of the solar back, I would exceed their number

 

[h2ofun]

The NEM-PS billing system is set up to disallow export credit in excess of your estimated generation. If you installed more solar than PTO docs, you could easily do it. A rogue battery system that could charge off-peak and discharge during Peak could also create excess export credits. The Tariffs clearly specify how they will penalize you by deducting from Peak first, Part-Peak second, then Off-Peak if you have excess exports.

A fully permitted and PTO'd Tesla system will never run into these limits.

Again, if I sent 100% of the solar back, all approved by pge, I would exceed their number

 

[miimura]

Again, if I sent 100% of the solar back, all approved by pge, I would exceed their number

What are the figures for "Estimated PV Generation" and your actual solar production during the same period?

Personally, I would be ecstatic if my system produced what PG&E estimated. My Dec 16-Jan 17th bill estimated 408 kWh and my monitoring system said I actually produced 115 during the same period.

 

[swedge]

I believe the limit is so you do not send back more than you were approved to do, which could impact things like safety with transformer size.

There are two issues here. Solar systems, any generation actually, face this capacity issue. This was covered in your original solar NEM interconnection request and permission to operate.

The other issue is related to battery systems which could grid charge cheap and then discharge to the grid during peak times, cashing in on the difference between peak and off-peak pricing. Electron arbitrage. This is not allowed and is why the couples billing calculates your monthly "estimated" production.

My solar installer gave me a document showing the info they filed with PG&E back when my solar was first installed. It includes tilt, azimuth, panel model number and count. The PTO mentioned only the last two. The NEM agreement estimated solar production and compared it to my historical consumption, but I am not finding any limitation, so it looks like this was just to keep consumers being ripped off by installers proposing oversized systems, the excess of which beyond consumption would result in only minimal credit.

One year my net kWh was negative and I did get a credit for the excess totaling 40¢ for the year.

 

[swedge]

If I sent 100% of the solar back, I would exceed their number

h2,

Where are you seeing "their number" which you might exceed? Is this on your PTO or on your monthly B&W bill?

SW

 

[h2ofun]

h2,

Where are you seeing "their number" which you might exceed? Is this on your PTO or on your monthly B&W bill?

SW

Okay, here is stuff close. First is my Feb still stating the max generation credit.

The second is the amount of solar I have made just in moth of Feb. My bill is from like the 18th, but it is close to show my point. And since I have 50% of my panels facing north,, ...

 

[Redhill_qik]

Okay, here is stuff close. First is my Feb still stating the max generation credit.

View attachment 773651

The second is the amount of solar I have made just in moth of Feb. My bill is from like the 18th, but it is close to show my point. And since I have 50% of my panels facing north,, ...

According to the CSI-EPBB calculator that is used for the PG&E estimate, for zipcode 95603, 45 Hanwha G6+340 panels with a Solaredge SE1140 with a tilt of 20 degrees and facing north (0 degrees) would generate 336 kWh for Jan and 588 kWh for Feb. The same facing south (180 degrees) would generate 1021 kWh for Jan and 1413 kWh for Feb. Extrapolating your February data of 1.52 kWh for the remaining 4 days comes to a total of 1848 kWh (1520+4*82) versus my CSI-EPBB estimate of 2001 kWh (588 + 1413). So, the PG&E system appears to not have your full array information in it which someone in the PG&E solar billing department should be able to confirm/rectify if you care to pursue it. You are getting the full credit for everything that you are exporting, so spending many hours to get it fixed would have no benefit other than your personal satisfaction.

I think that you have mentioned that the PV was installed in multiple phases, so that likely is the cause where the latest installation replaced the original installation instead of being added to it.

 

[h2ofun]

According to the CSI-EPBB calculator that is used for the PG&E estimate, for zipcode 95603, 45 Hanwha G6+340 panels with a Solaredge SE1140 with a tilt of 20 degrees and facing north (0 degrees) would generate 336 kWh for Jan and 588 kWh for Feb. The same facing south (180 degrees) would generate 1021 kWh for Jan and 1413 kWh for Feb. Extrapolating your February data of 1.52 kWh for the remaining 4 days comes to a total of 1848 kWh (1520+4*82) versus my CSI-EPBB estimate of 2001 kWh (588 + 1413). So, the PG&E system appears to not have your full array information in it which someone in the PG&E solar billing department should be able to confirm/rectify if you care to pursue it. You are getting the full credit for everything that you are exporting, so spending many hours to get it fixed would have no benefit other than your personal satisfaction.

I think that you have mentioned that the PV was installed in multiple phases, so that likely is the cause where the latest installation replaced the original installation instead of being added to it.

I called PGE solar yesterday. She told me that had all three of my PTO's in the system. For the first 46 panels. Then for the 5 batteries, And then for the second set of like 48 panels.

So this is why I just keep asking, since if they tell me they have all the panels, what can I do since it seems low?

 

[Redhill_qik]

I called PGE solar yesterday. She told me that had all three of my PTO's in the system. For the first 46 panels. Then for the 5 batteries, And then for the second set of like 48 panels.

So this is why I just keep asking, since if they tell me they have all the panels, what can I do since it seems low?

Likely because one database that tracks the PTO Interconnect Agreements has that information in text form and the billing system that is running the calculation only has the first 46 or the second 48 in it. Until you can get them to admit that the information actually being used by the billing calculation is incorrect you won't be satisfied.

 

[dareed1]

h2ofun,
Can you tell us which actual billing days does the February bill cover? I'm asking because our B/W statement is frequently more than a month behind. For example, the statement I received in mid-January actually covered 24 days in November and 6 days in December.

 

[h2ofun]

h2ofun,
Can you tell us which actual billing days does the February bill cover? I'm asking because our B/W statement is frequently more than a month behind. For example, the statement I received in mid-January actually covered 24 days in November and 6 days in December.

says statement date 2/16/22